Auth: Add anonymous users view and stats (#78685)

* Add anonymous stats and user table

- anonymous users users page
- add feature toggle `anonymousAccess`
- remove check for enterprise for `Device-Id` header in request
- add anonusers/device count to stats

* promise all, review comments

* make use of promise all settled

* refactoring: devices instead of users

* review comments, moved countdevices to httpserver

* fakeAnonService for tests and generate openapi spec

* do not commit openapi3 and api-merged

* add openapi

* Apply suggestions from code review

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>

* formatin

* precise anon devices to avoid confusion

---------

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>
Co-authored-by: jguer <me@jguer.space>

packages/grafana-e2e-selectors/src/selectors/pages.ts

@@ -310,6 +310,7 @@ export const Pages = {
     tabs: {
       allUsers: 'data-testid all-users-tab',
       orgUsers: 'data-testid org-users-tab',
+      anonUserDevices: 'data-testid anon-user-devices-tab',
       publicDashboardsUsers: 'data-testid public-dashboards-users-tab',
       users: 'data-testid users-tab',
     },